Department Process Engineering

VUNA – Nutrient Recovery from Urine

By recovering nutrients from urine, we develop a dry sanitation system, which is affordable, produces a valuable fertiliser, promotes entrepreneurship and reduces pollution of water resources.

Research

The VUNA Project researches on the following topics. Download the VUNA Final Report for a detailed overview on our results.

Nutrient Recovery Processes

Our body excretes the majority of nutrients in the urine (and not in the faeces). By collecting urine separately, we can recover valuable nutrients, e.g. nitrogen, phosphorus, potassium. At the same time, we prevent pollution of surface waters with high nutrient loads. 

VUNA Nutrient Recovery Pilot Plants

Eawag's fertiliser production: All toilets at Eawag's main building Forum Chriesbach divert the urine into a separate pipe system. After storage, a pilot treatment unit at the basement transforms the urine into a concentrated nutrient solution. 
eThekwini's fertiliser production: The urine collected from urine-diverting toilets in eThekwini is processed at the Newlands-Mashu test site. At a second site, the Prior Road Costumer Care Center, a treatment plant showcases that nutrient recovery can serve urban areas too. 

VUNA Nutrient Recovery Processes 

Nitrification and distillation: To recover all nutrients contained in urine and transform them into a suitable fertiliser product, the combination of two processes has proven to be efficient: In a first step, urine is stabilised in a bacterial process called nitrification. In a subsequent step, the stabilised urine is distilled and a concentrated nutrient solution is obtained. 
Electrolytic urine treatment: Electrolysis uses electric current to convert or remove pollutants. The advantages are that no bacteria or chemicals are needed. This allows easy process control and a high degree of automation.
Struvite precipitation: Struvite is a safe, bio-available and user-friendly fertiliser. It can be recovered from urine, contrary to conventional phosphate fertilisers, which have to be produced from phosphate rocks (a non-renewable resource).

Risks of Using Urine

Urine and Fertiliser Quality

The foremost goals of urine treatment are the recovery of nutrients for beneficial use. However, the urine treatment processes must also ensure that the end-products are safe to use, provide adequate human and environmental health protection, and are of adequate quality to ensure optimal market value. Pathogens and pharmaceuticals could potentially impact the quality of end products. 

Research activities:

  • Removing pharmaceuticals: The majority of pharmaceutical residues are excreted in the urine (and not the faeces). Hence, the separate collection of urine isolates pharmaceuticals and prevents them from entering the environment. Experiments showed that long-term storage is not sufficient to remove pharmaceuticals. Nevertheless, processes occurring during nitrification, are suitable to remove certain pharmaceuticals. Virtually all pharmaceuticals can be removed in an activated carbon filter.
  • Inactivating pathogens: Whereas some pathogens can be excreted in the urine, others are introduced from cross-contamination with faeces during urine collection. We evaluated the viability of representative pathogens during urine treatment. We observed partial disinfection through urine storage and nitrification. Distillation is assumed to eliminate all pathogens due to high temperatures. Research partners: Environmental Chemistry Laboratory at EPFL.

Agriculture

Testing VUNA fertilisers on crops

In VUNA affiliated projects, our fertilisers are being tested in South Africa and Switzerland. At the UKZN Agricultural Engineering Department in Pietermaritzburg, crop scientists fertilised maize in a pot trial with struvite, dehydrated and pasteurised latrine faecal sludge pellets and commercial superphosphate. First results have shown that struvite gave the best results as phosphorus fertilisers on clayey soils, but efficiency strongly depended on soil characteristics.

At ETH in Zurich, the Plant Nutrition Group produced isotope-marked struvite and nitrification/distillation product. The tests in ETHZ's greenhouse have shown that plants assimilate nutrients from VUNA fertilisers at least as readily as from commercial synthetic fertilisers.

Urine Collection Network

eThekwini Water and Sanitation introduced urine-diverting toilets as a system to supply sanitation to unserved regions, where water is scarce and water-borne sewer systems are too costly. Therefore a cost-efficient and optimised urine collection approach is necessary to harvest the valuable nutrients in urine.

Research activities:

  • Optimising urine collection: We aim to make urine collection more cost efficient. Therefore, we implemented a pilot urine collection scheme to gain experiences and suggest improvements. Based on the evaluated costs, we are currently developing a business plan.
  • Performance Modelling: The entire system of urine collection, transport and decentralised treatment consists of a large number of interconnected elements (e.g. toilets, storage tanks, treatment reactors) which influence the overall system performance (e.g. pollution control, urban hygiene, fertilizer production). Using a combination of system analysis and mathematical modelling we identified critical elements, evaluated the value of particular measurement schemes and estimated the overall system performance.

Social and Economic Aspects

The success of any sanitation programme depends on people's willingness to accept it. Urine-diverting toilets are still not well accepted by many. In order to increase acceptance, health and hygiene education is needed.

Research activities:

  • Social acceptance: We accompanied the introduction of the VUNA technologies with studies, which investigated the socio-cultural perceptions and factors influencing users’ acceptance. 
  • Campaigning for health & hyigene: Based on our findings from the acceptance studies, we developed appropriate educational activities and awareness material, e.g. for households and schools.
  • Incentives for urine production: By giving urine a financial value, we tested how to increase toilet use, improve hygiene, reduce loss of valuable nutrients and augment household income for the poorest.
  • Business model: To better understand the value chain from urine to fertiliser, we analysed the various components of the nutrient recovery system with a business perspective.

About us

An acronym, name and motto at the same time, VUNA stands for Valorisation of Urine Nutrients in Africa, and is the name of our project. In isiZulu, the language of the project area in the municipality of eThekwini, South Africa, the word 'vuna' means harvest. A healthy harvest follows a balanced nutrient application to the crops. And, in the case of the VUNA project, we harvest the necessary nutrients from urine.

Project Team

Steering Committee

Principal Investigators 

Project Coordination

Urine Treatment Processes

Risks of Using Urine

Agriculture

Urine Collection Networks

Social and Economic Opportunities

Bill & Melinda Gates Foundation 

Former Team Members

  • Complete Recovery: Michael Wächter, Mathias Mosberger, Maximilian Grau, Sara Rhoton
  • Nitrification: Alexandra Florin, Corine Uhlmann, Gabriel Kämpf
  • Distillation: Michael Wächter, Samuel Huber, Mischa Schwaninger, Thomas Gmeinwieser 
  • Electrolysis: Christina Fritzsche, Annette Remmele, Anja Sutter
  • Struvite: Maximilian Grau, Sara Rhoton, Merlien Reddy, Sibongile Maqubela, Mlungisi Mthembu, Samukelisiwe ‘Thandi’ Cele, Musawenkosi ‘Moussa’ Ndlovu 
  • Process Control: Ana Santos, Lorenzo Garbani Marcantini, Angelika Hess, Elisabeth Grimon
  • Pharmaceuticals: Birge D. Oezel Duygan, Annette Remmele
  • Pathogens: Manfred Schoger, Ariane Schertenleib, Sara Oppenheimer, Simon Schindelholz
  • Urine Collection: Peter Spohn, Lucky Sibiya
  • Performance Modelling: Theresa Rossboth, Thomas Hug, Andreas Scheidegger
  • Social Acceptance: Elisa Roma, Marietjie Coertzen
  • Incentives: Leeanne MacGregor
  • Business model: Luzius Etter
  • BMGF: Alyse Schrecongost 
  • Documentation: Corine Uhlmann, Nina Gubser, Susan Mercer

Documentation

For an overview on the VUNA Project, download the VUNA Final Report 2015. For more in-depth information, have a look at the news articles, videos, and publications below.

Videos

VUNA on YouTube

VUNA on TV

VUNA at the Faecal Sludge Management Conference 2012

Media coverage

English

Annual Report 2014 on the ETH Domain: Fertilize Plants Instead of Contaminating Water

The Mercury: Good soil and hard work

allAfrica.com: Harvesting nutrients that are flushed away

swissinfo.ch: Urine could hold secret to crop fertilisation

AlphaGalileo: Urine as a Commercial Fertilizer?

swissinfo.ch: Gates funds urine project in South Africa

swissinfo.ch: Breakthrough - How pee could help poor farmers (Radio)

zimbio: Number 1 New Fertilizer: Urine May Become Commercial Fertilizer

Washlink: Urine as a Commercial Fertilizer?

German

Technology Review: Geruchloser Dünger aus Urin

Deutschlandfunk: Dünger aus Urin

Aargauer Zeitung: Kein Mist, unser Pipi wird zu Dünger für unsere Blumenbeete

Radio Pilatus: Dünger aus Urin

Spektrum der Wissenschaft: Urin - der Dünger der Zukunft?

Der Spiegel: Gold aus Gülle und Knochen

Tages-Anzeiger: Urin ist zu schade zum Runterspülen

Deutschlandfunk: Forschung aktuell - Dünger aus Urin

Blick TV: Dieses WC macht aus Pipi Dünger (Video)

SF Tagesschau: Cleantec City für eine saubere Zukunft (Video)

Der Bund: Ausblick auf eine saubere Zukunft

NZZ am Sonntag: Die Zukunft liegt im Urin

Pressetext: Südafrika testet Verwertung von Urin

Basler Zeitung: Bill Gates finanziert Schweizer Projekt

Der Bund: Bill Gates finanziert Schweizer Projekt

Tages Anzeiger: Bill Gates finanziert Schweizer Projekt

myScience: Urin als Rohstoff der Zukunft?

nachhaltigkeit.org: Abwasserklärung mit Bill Gates

DRS 1: Urin bald als Dünger? (Radio)

French

Terre & Nature: L'urine sert d'engrais

20 minutes: Un projet suisse de séparation des urines

Portuguese

O Valor Econômico: Caminhos para o Rio

Publications – Conference Papers (Incl. Downloads)

VUNA in General

Nutrient Recovery Processes

Urine Collection Networks

Social and Economic Aspects

Publications – Referenced (with Links to RefWorks)

Nutrient Recovery Processes

Risks of Using Urine

Agriculture

Urine Collection Networks

Social and Economic Aspects

Publications – (Not) yet Referenced

Urine Treatment Processes

  • Fumasoli, A. (2015) Stabilization of urine with nitrification as pre-treatment for nutrient recovery (preliminary title). PhD thesis, ETH Zurich. In preparation.
  • Fumasoli, A., Morgenroth, E., Udert, K.M. (2015) Modeling the low pH limit of nitrosomonas-type bacteria in high-strength nitrogen wastewaters. Submitted to Water Research.
  • Fumasoli, A., Weissbrodt, D., Wells, G.F., Bürgmann, H., Mohn, J., Morgenroth E., Udert K.M. (2015) Low pH selects for nitrosococcus in high and nitrosospira in low salt environments. In preparation.
  • Grau, M.G.P., Rhoton, S., Brouckaert, C.J., Buckley, C.A. (2015) Development of a fully automated struvite reactor to recover phosphorus from source-separated urine collected at urine diversion toilets in eThekwini. Accepted for Water SA.
  • Grimon, E. (2015) Sensor characterization & monitoring for soft-sensing of urine nitrification systems (preliminary title). Master’s thesis, ETH Zurich. In preparation.
  • Hess, A. (2015) Feasibility of UV-Vis spectrophotometry for nitrite esti- mation in urine nitrification systems. Master’s thesis, ETH Zurich. In preparation.
  • Mašić, A., Santos, A., Etter, B., Udert, K.M., Villez, K. (2015) Estimation of nitrite in source-separated nitrified urine with UV spectrophotometry. In preparation.
  • Udert, K.M., Buckley, C.A., Wächter, M., McArdell, C.S., Kohn, T., Strande, L., Zöllig, H., Fumasoli, A., Oberson, A., Etter, B. (2015) Technologies for the treatment of source-separated urine in the eThekwini Municipality. Water SA 41(2), 212-221.
  • Uhlmann, C. (2014) Complete nitrification of urine. Master’s thesis, ETH Zurich.
  • Wächter, M., Huber, S., Kluge, J., Mazzotti, M., Udert, K.M. (2015) Selective crystallization of sodium chloride (NaCl) from partially nitrified urine. In preparation.
  • Wächter, M., Schwaninger, M., Gmeinwieser, T., Udert K.M. (2015) Safety assessment for production and storage of nitrified and concentrated fertilizer from human urine. In preparation. Zöllig, H. (2015) Electrolysis for the treatment of stored source-separated urine (preliminary title). PhD thesis. ETH Zurich. In preparation.
  • Zöllig, H., Fritsche, C., Morgenroth, E., Udert, K. M. (2015) Direct electro-chemical oxidation of ammonia on graphite as a treatment option for stored source-separated urine. Water Research 69, 284-294.
  • Zöllig, H., Morgenroth, E., Udert, K.M. (2015) Inhibition of direct ammonia oxidation due to a change in local pH. Accepted for Electrochimica Acta.
  • Zöllig, H., Remmele, A., Fritzsche, C., Morgenroth, E., Udert, K.M. (2015) Formation of chlorination by-products and their emission pathways in chlorine mediated electro-oxidation of urine on active and inactive anodes. Submitted to Environmental Science and Technology.
  • Zöllig, H., Remmele, A., Morgenroth, E., Udert, K.M. (2015) The removal of ammonia and organic substances from real stored urine by chlorine mediated electro-oxidation – effects of urine composition and electrode material. In preparation.

Risks of Using Urine

  • Bischel, H.N., Oezel, B.D., Strande, L., McArdell, C.S., Udert, K.M., Kohn, T. (2015) Pathogens, pharmaceuticals and antibiotic resistance genes in source-separated urine in eThekwini, South Africa. In preparation.
  • Bischel, H.N., Schertenleib, A., Fumasoli, A., Udert, K.M., Kohn, T. (2014) Inactivation kinetics and mechanisms of bacterial and viral pathogen surrogates during urine nitrification. Environmental Science: Water Research & Technology 1, 65-76.
  • Bischel, H.N., Schindelholz, S., Schoger, M., Decrey, L., Bosshard, F., Udert, K.M., Kohn, T. (2015) Bacteria inactivation during drying of struvite fertilizers produced from stored urine. In preparation.
  • Decrey, L. (2015) Virus inactivation in human excreta and animal manure. PhD thesis, EPF Lausanne.
  • Oezel Duygan, B.D., Udert, K.M., Remmele, A., McArdell, C.S. (2015) Fate of pharmaceuticals in source-separated urine during storage, biological treatment and powdered activated carbon adsorption. In preparation.
  • Oezel, B.D. (2013) Fate of pharmaceuticals during urine treatment in laboratory batch experiments: can urine be used as fertilizer in South Africa? Master’s thesis, ETH Zurich.
  • Schertenleib, A. (2014) Inactivation of pathogens in urine nitrification reactors. Master’s thesis, EPF Lausanne.
  • Schoger, M. (2011) Bacterial inactivation in struvite recovered from urine in South Africa. Master’s thesis, EPF Lausanne.

Agriculture

Urine Collection Networks

  • Hug,T., Maurer, M. (2012) Stochastic modeling to identify requirements for centralized monitoring of distributed wastewater treatment. Water Science & Technology, 65(6), 1067-1075.
  • Joseph, H.R. (2015) Develop and describe a suitable logistic collection system for urine harvesting in eThekwini. Master’s thesis, University of KwaZulu-Natal. In preparation.
  • Rossboth,T., Udert, K.M., Maurer, M. (2015) Using stochastic modelling to support urine collection scheme planning in South Africa. In preparation.
  • Rossboth, T. (2013) Model-based systems analysis of the collection management of source-separated urine in eThekwini Municipality, South Africa. Master’sThesis, University of Natural Resources & Life Sciences (BOKU), Vienna.

Social and Economic Aspects

  • Etter, B., Etter, L., Joseph, H.R., Grau, M.G.P., Chetty, S., Gounden, T., Gebauer, H., Udert, K.M. (2015) Financial opportunities for complete nutrient recovery from source-separated urine in eThekwini, South Africa. In preparation.
  • Mkhize, N. (2015) The role of health & hygiene education in the accept- ance, utilisation, and maintenance of urine diversion toilets in rural communities of KwaZulu-Natal (preliminary title). Master’s thesis, University of KwaZulu-Natal. In preparation.
  • Mkhize, N., Taylor, M., Ramsay, L.F., Buckley C.A., Gounden, T. (2015) Urine-diverting toilets acceptance, use and maintenance: through users eyes. In preparation.
  • Okem, A.E., Xulu, S., Tilley, E., Buckley, C., Roma E. (2013) Assessing perceptions and willingness to use urine in agriculture: a case study from rural areas of eThekwini municipality, South Africa. Journal of Water Sanitation and Hygiene for Development 3(4), 582-591.
  • Ramsay, L.F., Coertzen, M., Buckley, C.A., Gounden, T. (2015) The power of perception: views and practices related to urine diversion toilets in the eThekwini Municipality, South Africa. In preparation.
  • Roma, E., Philp, K., Buckley, C., Xulu, S., Scott, D. (2013) User percep- tions of urine diversion dehydration toilets: Experiences from a cross- sectional study in eThekwini Municipality. Water SA 39(2), 305-312.
  • Tilley, E. (2015) Acceptance, impact & feasibility of incentives for increasing toilet use: a case study in eThekwini, South Africa. PhD Thesis, ETHZ.
  • Tilley, E., Logar, I., Guenther, I. (2015) Giving respondents time to think about a conditional cash transfer program: a choice experiment in rural South Africa. In preparation.
  • Tilley, E., Guenther, I. (2015) The impact of conditional cash transfers on toilet use. In preparation.
  • Tilley, E. (2015) Cost-effectiveness and community impacts of two urine-collection programs in rural South Africa. In preparation.
  • Tilley, E., Günther, I. (2014) Mobile phones for collecting WaSH data in low-income countries. WEDC International Conference.